In putters, it is desirable to arrange that the putter-head behaves like a free body at impact and to control various parameters of the putter-head such as its principal moments of inertia, the position of its center of mass and the impact face shape in order to improve spin and velocity characteristics imparted on a ball at impact. These improvements comprise greater imparted topspin or reduced backspin and a reduction in the variation of putt length as a function of impact height.